US4984126A - Method and circuit for stopping the test run of a rotor being balanced - Google Patents

Method and circuit for stopping the test run of a rotor being balanced Download PDF

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Publication number
US4984126A
US4984126A US07/241,847 US24184788A US4984126A US 4984126 A US4984126 A US 4984126A US 24184788 A US24184788 A US 24184788A US 4984126 A US4984126 A US 4984126A
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United States
Prior art keywords
voltage
electromagnetic coil
flip
flop
movable member
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Expired - Fee Related
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US07/241,847
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English (en)
Inventor
Karl Rothamel
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Hofmann Werkstatt Technik GmbH
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Hofmann Werkstatt Technik GmbH
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Assigned to HOFMANN WERKSTATT-TECHNIK GMBH, WERNER-VON-SIEMENS-STRASSE 2, 6102 PFUNGSTADT reassignment HOFMANN WERKSTATT-TECHNIK GMBH, WERNER-VON-SIEMENS-STRASSE 2, 6102 PFUNGSTADT ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ROTHAMEL, KARL
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M1/00—Testing static or dynamic balance of machines or structures
    • G01M1/02—Details of balancing machines or devices
    • G01M1/06—Adaptation of drive assemblies for receiving the body to be tested

Definitions

  • the invention relates to a method and circuit for stopping the test run of a rotor being balanced, and more particularly to a method and circuit for stopping the test run of a rotor being balanced using an electromagnetic brake.
  • the test run of the rotor to be balanced is stopped with the aid of an electromagnetic brake, which is provided with a magnetic element having a potted coil.
  • the brake also includes a friction lining secured to the magnetic element or stator and an armature element comprising an armature disk, which is subjected to a spring force so that an air gap is provided between the magnetic element and the armature element when the brake is released.
  • the armature element is connected to that part of the machine, which must be stopped, for example a motor shaft of an electric motor for driving the primary shaft of the balancing machine.
  • the air gap is adjusted to a rated size.
  • a method according to the present invention in which the intensity of the supply voltage is reduced when the armature disk is applied to the friction lining and then maintained at an intensity which overcomes the spring force, while the armature disk is applied to the friction lining, in order to attain a reduced braking moment compared with the rated braking moment.
  • the circuit arrangement according to the invention performs this method with the aid of a monitoring circuit that processes the supply voltage of the electromagnet coil and triggers a switch connecting the electromagnet coil to the voltage supply source.
  • the switch When the supply voltage increase is interrupted, which occurs when the armature disk meets the friction lining, the switch turns off a first voltage supply, which was applied to the electromagnet coil upon actuation and is at least equivalent to the rated voltage, and supplies a reduced second supply voltage to the electromagnet coil, thereby producing the desired braking torque.
  • One advantage of the present invention is that once the braking process is initiated to stop the test run, the braking moment does not attain the level of the high rated braking moment needed when the electromagnet brake is functioning as a holding brake, for instance when the tensioning nut is being tightened. Instead, a lower braking moment is attained, which assures gentle, non-jerking braking.
  • the electromagnet brake can be operated both at the rated braking moment, as a holding brake for tightening the tensioning nut of the clamping device, and at the substantially reduced braking moment, as a service brake for stopping the primary shaft of the balancing machine after the test run. The rated braking moment is not attained when the braking process is initiated for braking the test run, so that the aforementioned gentle braking is assured.
  • the supply current in this brake rises until the force of the spring engaging the armature disk is overcome, and the armature disk moves toward the magnetic element (stator) of the electromagnetic brake.
  • This motion may also be an uneven one, caused by irregularities in the spring or in the magnetic field.
  • the spring force engaging the armature disk can be overcome, and once the armature disk is resting on the friction lining, the braking moment can be reduced by reducing the supply current to the electromagnetic coil.
  • an electric circuit arrangement In order to stop the test run with reduced braking moment, an electric circuit arrangement is used that has a monitoring circuit, which monitors and evaluates the supply current flowing through the electromagnetic coil with a rated voltage applied. This monitoring circuit triggers a switch so that the particular supply voltage is applied to the electromagnetic coil of the electromagnetic brake. If this monitoring circuit detects an interruption in the supply current increase, the switch is triggered, such that the initially switched-on rated voltage, or a supply voltage at a higher level than the rated voltage, is switched off. In this first phase, the armature disk is brought into contact with the friction lining, across the air gap, counter to the force of the spring.
  • the braking moment that is then desired is established by means of a second supply voltage, which is reduced by comparison with the rated voltage and is applied to the electromagnetic coil.
  • the switch can be triggered after a delay. This assures that even if the armature disk is not guided precisely parallel across the air gap to the friction lining, the reduced supply current will not be supplied to the electromagnetic coil until the armature disk rests entirely on the friction lining. Even if the motion of the armature disk across the air gap is tilted, it is assured that the desired reduced braking moment comes into effect whenever the entire armature disk is located in the braking position, or in other words rests completely on the friction lining.
  • the advantages achieved by the present invention are that rotation of the wheel on the primary shaft of the balancing machine is avoided during braking of the test run and the electromagnetic brake can be used as both a holding brake and as a jerk-free service and positioning brake. Because the braking moment is constant over the rpm range, a shortened braking time and thus a shorter cycling time are attained. Actuating the holding brake, for example by a foot switch, does not cause rotation of the wheel on the primary shaft. At rotational speeds, i.e. rpm, above a threshold value, the service brake is activated first, and then, only when a reduced rpm is achieved, the holding brake is activated.
  • the electric motor which in conventional balancing machines is also used for braking the test run, for example by means of a pulsating direct current or by reversing the direction of rotation in the case of three-phase current, does not become heated, so that an additional fan for cooling the electric motor is unnecessary.
  • Electric motors of a relatively low insulation class can be used.
  • the trigger circuit for the electromagnet brake can be equipped with semiconductors that function in the low-voltage range, which provides increased operational safety.
  • FIG. 1 is a block circuit diagram of a preferred embodiment of the circuit arrangement for triggering an electromagnetic coil of an electromagnet brake for stopping the test run of a rotor to being balanced by a balancing machine of the present invention.
  • FIG. 2 is a graph depicting the course of the supply current with the rated voltage switched on and with an ensuing reduced operating voltage in the electromagnetic coil of the electromagnetic brake.
  • an electromagnetic coil 3 of an electromagnetic brake is connected via a switch 2 having two switch positions a and b to a voltage supply source 1.
  • a resistor R is incorporated in the current circuit of the electromagnetic coil 3.
  • the voltage at the resistor R is delivered to a differentiation circuit 4 and a peak voltage detector 7.
  • a comparator 5 is connected to the output of the differentiation circuit 4, and a controllable delay stage 6 is connected to the output of the comparator 5.
  • the controllable delay stage 6 is controlled by the peak voltage detector 7.
  • the comparator 5 triggers a bistable multivibrator 8 in the form of a flip-flop via the controllable delay stage 6.
  • the bistable multivibrator 8 triggers the switch 2.
  • a monitoring circuit for monitoring the particular operating state of the brake is provided in the connecting line between the bistable multivibrator 8 and the switch 2.
  • a trigger line is provided, which is carried not only to the current supply source 1 but also to the bistable multivibrator 8 and the peak voltage detector 7 to switch on a particular operating state.
  • a starting pulse is supplied via the trigger line, marked “Triggering" in FIG. 1, to the voltage supply source 1 and the bistable multivibrator 8 to start the brake phase. Because of this starting pulse, the bistable multivibrator 8 assures that the switch 2 will be in position a.
  • a supply voltage which is equivalent to or higher than the rated voltage is supplied to the electromagnetic coil 3 of the electromagnetic brake.
  • the supply current I flowing through the electromagnetic coil 3 increases with time t, as shown in FIG. 2. During this increase, the armature disk moves across an air gap and comes to rest on the friction lining. When the armature disk is applied to the friction lining, the continuous increase of the supply current is interrupted.
  • a reduced supply voltage be applied to the electromagnetic coil 3. This is attained by monitoring the supply current of the electromagnetic coil with the aid of the voltage picked up at the resistor R.
  • the voltage present at the resistor R is delivered to the differentiation circuit 4, which detects the interruption of the supply current increase, for example in the form of the two peak points shown in FIG. 2, and sends a corresponding signal to the comparator 5.
  • the comparator 5 evaluates the signal emitted by the differentiation 4 and triggers the bistable multivibrator 8 in the form of a flip-flop.
  • the bistable multivibrator 8 To assure that the bistable multivibrator 8 will not be triggered by the output signal of the comparator 5 until the armature disk rests completely on the friction lining, the controllable delay stage 6, which is set by the peak voltage detector 7, is interposed between the peak voltage detection and the bistable multivibration 8. Once this set delay period has elapsed, the bistable multivibrator 8 is actuated, for example is reset, and causes the switch 2 to return to the switch position b. As a result, the reduced supply voltage V2 (operating voltage) is then applied to the electromagnet coil 3, and an operating current I2 which brings about the desired braking moment flows in this coil. To compensate for aging of the brake components and tolerances of the brake components, the magnitude of the supply voltage V2 may be variable. A digital-analog converter, not shown in further detail, may for instance be used to this end. In this way, the desired braking moment for the service brake function of the electromagnetic brake is always attainable.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Braking Arrangements (AREA)
US07/241,847 1987-09-08 1988-09-08 Method and circuit for stopping the test run of a rotor being balanced Expired - Fee Related US4984126A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19873730084 DE3730084A1 (de) 1987-09-08 1987-09-08 Verfahren zum stillsetzen des messlaufs eines auszuwuchtenden rotors
DE3730084 1987-09-08

Publications (1)

Publication Number Publication Date
US4984126A true US4984126A (en) 1991-01-08

Family

ID=6335505

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/241,847 Expired - Fee Related US4984126A (en) 1987-09-08 1988-09-08 Method and circuit for stopping the test run of a rotor being balanced

Country Status (4)

Country Link
US (1) US4984126A (enrdf_load_stackoverflow)
EP (1) EP0306669B1 (enrdf_load_stackoverflow)
DE (1) DE3730084A1 (enrdf_load_stackoverflow)
ES (1) ES2023234B3 (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5255563A (en) * 1990-09-06 1993-10-26 Hofmann Werkstatt-Technik Gmbh Apparatus for retarding the measuring spindle of a balancing machine
GB2381052A (en) * 2001-10-17 2003-04-23 Lansing Linde Ltd Evaluating coil current in an electromagnetically releasable brake
CN102843087A (zh) * 2012-09-12 2012-12-26 西安交通大学 一种在线磁平衡头励磁线圈的驱动装置

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3923191C2 (de) * 1989-07-13 1994-02-24 Hofmann Werkstatt Technik Vorrichtung zum Messen der Unwucht eines Rotors, insbesondere eines Kraftfahrzeugrades
US5543672A (en) * 1989-10-18 1996-08-06 Yazaki Corporation Rotation detecting device with magnet brake
CN114856936B (zh) * 2022-04-27 2024-09-24 西安热工研究院有限公司 一种检测在役电机电磁抱闸性能的工装及方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE411299C (de) * 1925-03-26 Magnet Werk G M B H Eisenach F Einrichtung bei elektromagnetischen Reibungskupplungen
DE560168C (de) * 1930-07-04 1932-09-29 Demag Akt Ges Elektromagnetisch gesteuerte Wellenkupplung
US4360855A (en) * 1979-11-27 1982-11-23 Nippondenso Co., Ltd. Injector drive circuit
US4480472A (en) * 1982-08-10 1984-11-06 Hofmann Corporation Automotive Service Equipment Electronic wheel balancer for vehicle wheels
US4631627A (en) * 1985-05-09 1986-12-23 Morgan Ronald E Impulse operated relay system
US4641219A (en) * 1983-07-12 1987-02-03 Sharp Kabushiki Kaisha Low noise solenoid drive
US4737882A (en) * 1987-02-09 1988-04-12 Honeywell Inc. Proportional solenoid valve control circuit

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE411299C (de) * 1925-03-26 Magnet Werk G M B H Eisenach F Einrichtung bei elektromagnetischen Reibungskupplungen
DE560168C (de) * 1930-07-04 1932-09-29 Demag Akt Ges Elektromagnetisch gesteuerte Wellenkupplung
US4360855A (en) * 1979-11-27 1982-11-23 Nippondenso Co., Ltd. Injector drive circuit
US4480472A (en) * 1982-08-10 1984-11-06 Hofmann Corporation Automotive Service Equipment Electronic wheel balancer for vehicle wheels
US4641219A (en) * 1983-07-12 1987-02-03 Sharp Kabushiki Kaisha Low noise solenoid drive
US4631627A (en) * 1985-05-09 1986-12-23 Morgan Ronald E Impulse operated relay system
US4737882A (en) * 1987-02-09 1988-04-12 Honeywell Inc. Proportional solenoid valve control circuit

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Simplatroll Brake Brochure, by Lenze Antriebstechnik, Postfach 1250, D 4923 Extertal, Sitz, Printed in Germany by L/LEX/12.85, pp. 2 5 and cover. *
Simplatroll-Brake Brochure, by Lenze Antriebstechnik, Postfach 1250, D-4923 Extertal, Sitz, Printed in Germany by L/LEX/12.85, pp. 2-5 and cover.

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5255563A (en) * 1990-09-06 1993-10-26 Hofmann Werkstatt-Technik Gmbh Apparatus for retarding the measuring spindle of a balancing machine
GB2381052A (en) * 2001-10-17 2003-04-23 Lansing Linde Ltd Evaluating coil current in an electromagnetically releasable brake
GB2381052B (en) * 2001-10-17 2005-05-18 Lansing Linde Ltd Method for operating a brake which has an electromagnet and electronic controller therefor
CN102843087A (zh) * 2012-09-12 2012-12-26 西安交通大学 一种在线磁平衡头励磁线圈的驱动装置
CN102843087B (zh) * 2012-09-12 2015-10-28 西安交通大学 一种在线磁平衡头励磁线圈的驱动装置

Also Published As

Publication number Publication date
EP0306669A1 (de) 1989-03-15
EP0306669B1 (de) 1991-05-29
DE3730084A1 (de) 1989-03-16
DE3730084C2 (enrdf_load_stackoverflow) 1991-04-11
ES2023234B3 (es) 1992-01-01

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Owner name: HOFMANN WERKSTATT-TECHNIK GMBH, WERNER-VON-SIEMENS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ROTHAMEL, KARL;REEL/FRAME:005070/0229

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FP Expired due to failure to pay maintenance fee

Effective date: 19990108

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Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362